5. PROFINET Network design - Peter Brown

PROFINET

Design

Pete Brown

Siemens Customer

Services

Pete Brown / PROFINET Design

PROFINET is 100% Ethernet


PROFINET is Ethernet

Ethernet is the established standard in the IT world for fast

exchange of data (IEEE 802.3)

PROFINET is always full duplex simultaneous communication

in two directions

PROFINET is always

"switched Ethernet"

Distribution of network load

can be influenced using topology

As comparison: PROFIBUS

One line to which all nodes

are connected

Performance directly

dependent on number of

nodes Controller

Slaves

Devices

100 Mbit/s full duplex

Switches connected into a line

Master

100 Mbit/s

100 Mbit/s

PROFINET Technology at a glance 3

Pete Brown / Engineering with PROFIsafe

PROFINET

is 100% switched Ethernet

PROFINET

uses IT standards such as TCP/IP

PROFINET

is real-time and deterministic

TCP/IP

n-1 n 2 1

IO data

Ethernet

header

IP

header

TCP

header Application data

Ethernet

trailer

100 Base TX (Twisted Pair) 4


Switch Switch RJ-45 jack

TP cable with RJ-45 plug

100 Base FX (optical FE) 5


According to IEEE 802.3 Clause 26:

Glass fiber cable for transmission of light/signals.

The nodes are connected via a switch that provides a port for

each node.

Switch Switch

Fiber-optic cable:

Distance depending on fiber type and network

component

Examples:

• 3 km - multimode fiber (62.5/125 or 50/125 µm)

• 26 km - single mode fiber (10/125 or 9/125 µm)

• …

Transfer Media - Comparisons 6


Twisted Pair Network Fibre Optic Network Wireless Network

Inter Building Networking No Yes Yes

Suitability for High Transmission Rates Partly Yes No

Max. Network Expansion 5000m Upto 150km 1000m/segment

Max. Distance between Two Network Nodes

100m

50m POF 100 PCF

3000m Multi Mode 15km Single Mode

30m/segment (indoor)

100m/segment (outdoor)

Max. Connecting Cable Length 100m

50m POF 100 PCF

3000m Multi Mode 15km Single Mode

100m to AP

Assembly Onsite Without Special Tool With Special Tool Specialist Personnel

Redundant Network Structures Electrical Ring Optical Ring Use of Different

Frequencies (2.4Ghz/5Ghz)

Industrial Twisted Pair cable 7


(FO) Classification 8


Core dia.: 100-300µm

Coating dia.: 200-1000µm

e.g.: Plastic Optical Fibre (POF)

Core dia.: 50 / 62,5 / 85 / 100µm

Coating dia.: 125 / 140µm

e.g.: Glass Multi-Mode

Fibre longitudinal section

with typical steel propagation Refractive index

profile

Fibre cross section

50um

125um

250um

280um

125um

9um

Core dia.: 8-10µm

Coating dia.:125-140µm

e.g.: Glass Mono-Mode

Ethernet Media Access Control (MAC) 9


Media Access Control (Layer 2a) defines the formatting of the data (framing) and the

medium access method.

Structure of the MAC frame:

8 bytes

Ethernet frame

MAC header

Destination

address Source

address Length

or type

User

data FCS

6 bytes 6 bytes 2 bytes 46 - 1500 bytes 4 bytes

Preamble

/SFD

Preamble: For synchronizing the clock pulses of the station

SFD (Start Frame Delimiter): Start pattern for the beginning of the frame

Destination / source address Ethernet destination/source address (MAC)

Length : Number of bytes in the data field

Type: Protocol type of the higher-level layer (e.g.IPv4 = 0x0800)

User data: (>46 <= 1500 bytes)

FCS (Frame Check Sequence): CRC checksum

Open standard in practice


Implementation in products

PROFINET is open for every type of standard Ethernet

communication (e.g. TCP/IP)

See also Web tools

Openness of PROFINET for every manufacturer of

automation equipment large and continuously

growing product portfolio

Simple PROFINET integration using software stack for

device manufacturer

Example applications

Access to controllers per Web browser

Standard Ethernet devices such as PCs for saving

measured data and for quality assurance in a machine

Expansion of an existing infrastructure by additional

PROFINET networks

Re

al-

tim

e

RT IRT Ethernet

TCP/UDP

PROFINET applications IT applica-

tions e.g.

HTTP

SNMP

DHCP...

Configuration diagnostics

Process data

IP

No

n-

real-

tim

e

Structure of PROFINET Telegrams 11


Standardized telegram format according to IEEE 802.3

Ether type according to IEEE for PROFINET real-time telegrams

0x0800: IP telegram

0x8892: PROFINET real-time telegram

Allocation of the received data via the Frame-ID

Cyclical transmission (process values) 8100 C000 hex

Event triggered transmission (alarms and events) 8100 A000 hex

Status information

Device and data status (e.g. Run, Stop, Error)

Pre-

ambel

7 Byte

Dest.

MAC

6 Byte

Source

MAC

6 Byte

VLAN*

4 Byte

Frame

ID

2 Byte

FCS

4 Byte

Prozess data

up to 1440 Byte

Sync

1 Byte

Ether-

type

2 Byte

Ethernet Frame

Status

Information

4 Byte

PROFINET specific Ethernet-Standard

* According to 802.1 Q

One cable for all purposes 12

Pete Brown / Engineering with PROFIsafe

The right topology for every system

Support of various topologies such as star, tree, line or

ring

Various media available for networking: Cat5 copper

cable, glass and plastic fiber-optic cables, and IWLAN

Access to machines and plants over a secure VPN

connection, e.g. for remote maintenance purposes

Topology based on design

Smaller cabling overhead and easier commissioning

Line topology and redundant ring structures possible

without additional network components

Several controllers can be operated in one network

simultaneous access to one device with Shared Device

and I-Device

Line (Redundant) ring

Star Tree

Wireless communication

(IWLAN) PROFINET

PROFIsafe

Device Name / Update Cycle 13


Offline engineering Online diagnostics Web view

Any questions? Peter Brown

Product Specialist

Siemens Customer Services

Mobile: 07808 825551

Email: [email protected]

5. PROFINET Network design - Peter Brown

Engineering

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